I just saw this over at WoWInsider earlier that Gamespy recently had a exclusive interviewed with Blizzard’s Jeff Kaplan about WotLK and about Death Knights. Its Interesting with a bit of details about the coming of Death Knights and how they somewhat going to work as tanks. Think cross of Magical tank with a feel of Fury Warrior and Enhancement Shaman kinda if you can imagine with ability to summon creatures and cast DoT diseases and all the rune magic stuff.
Anyway I rather you read the article your self as well as watch all the video clips of the WotLK scenery. WotLK has some amazing and spectacular scenery to check out all the exclusive clips as well as the 10 min video clip interview of Jeff Kaplan.
Gamespy exclusive of WotLK with Blizzard.